Drop Julia, assign one primary language per M3 sim spec

Ranked languages per spec by fit; took only the top pick:
- M3a (statistical): R — native stats ecosystem
- M3b (sociological): Prolog — equilibria as constraint satisfaction
- M3c (AMM): Solidity — on-chain-equivalent precision
- M3d (MEV): Fortran — dense PDE/knapsack numerics, no GC
- M3e (tokenomics): Fortran — SDE/VAR matrix loops, same toolchain as M3d
- M3f (consensus): Prolog — Markov/Nash as declarative search
- M3g (microstructure): Zig — tick-level latency, deterministic memory
- Hub: updated to reflect per-spec assignments

Julia removed project-wide: JIT startup cost and large toolchain
not justified when the project isn't going all-in on a single runtime.

core/docs/plans/M3d-mev-adversarial-sims.md

@@ -19,9 +19,9 @@ optimization C3 (emerging — SMFRL solvers); Kolokoltsov adversarial C3 (non-li
 WENO discretization established but crypto application novel). Parameterization C1.
 
 ## 3. Language & location
-TBD · `src/economy/sims/mev/`. Needs combinatorial optimization (OR-Tools for knapsack),
-continuous-time auction modeling, PDE solvers (WENO for shock-capturing in adversarial dynamics),
-and bilevel optimization (DSMFG). Julia or Fortran.
+TBD · `src/economy/sims/mev/`. **Fortran** — dense numerical loops for PDE solvers (WENO
+shock-capturing), knapsack combinatorics, and continuous-time auction modeling at the throughput
+MEV extraction demands; no GC pauses during hot-path simulation.
 
 ## 4. Does / does-not
 - **Does:** simulate Priority Gas Auctions where multiple searcher bots compete for the same